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Running techron on a DI car won't help as no fuel passes over the valves.
Past time for the Walnut Blast.

The DI cars have a design flaw the causes carbon build up over the valves.
No fuel passes over the valves. This is not unique to BMW.

I have a feeling that figure is off by an order of magnitude.

10.4 million miles???
For anyone who might not know, the valve is at the bottom end of that 'stem' you see coming down from the top. Only a portion of it is visible. The worst accretion is on the intake roof where the valve stem enters the cylinder head. The pic would have been taken after the intake manifold was removed. If a borescope is available you can see the same area without removing the intake manifold.

Hmm.. I'd not thought of that before. So this is an air intake valve on a DI car? Presumably the carbon is sucked in from the combustion chamber and builds up over time?

Reburn from the PCV line. The crankcase vents into the intake with oil vapor in it. Most of the vapor is burned in the combustion cycle, but some carbonizes on contact with the hot metal around the valve. Another bit of anti-pollution joy.

In a Port Injection system, the fuel contacts the valve stem and helps keep it clean. In a Direct Injection system, you don't get this effect.

Reburn from the PCV line. The crankcase vents into the intake with oil vapor in it. Most of the vapor is burned in the combustion cycle, but some carbonizes on contact with the hot metal around the valve.

So seafoam hooked to the PCV return once in a while should help?

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Six Euro Deliveries since December 1998 (Owned E46, E90, E91, E92 and E93)

its 139,000 and yes mega bills. The dealer tried to bend me over this week Monday they called me telling me I would have to pay them $400 to inspect the valves and that its normally 10hrs on average to clean the valves and they have to rent the equipment from BMW and bill me for it. Umm can you say F U. I said I'll just take the car and do it myself. I bought a set of gaskets and set about pulling my car to bits. Took me an hour to pull the thing to the intake and its taking 2hrs to hand clean each valve inlet.

its 139,000 and yes mega bills. The dealer tried to bend me over this week Monday they called me telling me I would have to pay them $400 to inspect the valves and that its normally 10hrs on average to clean the valves and they have to rent the equipment from BMW and bill me for it. Umm can you say F U. I said I'll just take the car and do it myself. I bought a set of gaskets and set about pulling my car to bits. Took me an hour to pull the thing to the intake and its taking 2hrs to hand clean each valve inlet.

Respect. Hope this cures the car.

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Six Euro Deliveries since December 1998 (Owned E46, E90, E91, E92 and E93)

I want to kick myself because its pretty simple to work on. I am sick of the dealer and I`ll not be returning in any kind of hurry. They billed me $300 to replace a functioning coil pack that they diagnosed as faulty.

I want to kick myself because its pretty simple to work on. I am sick of the dealer and I`ll not be returning in any kind of hurry. They billed me $300 to replace a functioning coil pack that they diagnosed as faulty.

So, since much of that is from the PCV, an oil catch can helps as a preventative mod, right?

I didn't think my OCC was doing anything, since there was only just a touch of oil on the end of the "dipstick" the can has (it's a BSH). Was mucking around on something else and decided to pull it off to empty it and see.

It had about an ounce of oil in it after the 1000 miles. More than I thought was there. FWIW, my car has not required oil between changes (so far).

its 139,000 and yes mega bills. The dealer tried to bend me over this week Monday they called me telling me I would have to pay them $400 to inspect the valves and that its normally 10hrs on average to clean the valves and they have to rent the equipment from BMW and bill me for it. Umm can you say F U. I said I'll just take the car and do it myself. I bought a set of gaskets and set about pulling my car to bits. Took me an hour to pull the thing to the intake and its taking 2hrs to hand clean each valve inlet.

I know they are full of crap. I also turned in the stupid questionnaire today. I did asked for my money back for the coil pack they replaced without even so much as trouble shooting. Not till I brought the car back that afternoon did they bother to try the pack in another cylinder before deciding it was something else. If it was BMW they did this too BMW would have laughed at them. But no they have my money so hard luck. They gave me some crap about it should have been replaced when the plugs and injectors where so no refund.. LOL

I am thinking about filing a claim with my cc about this lot. 800 in parts and 2200 in labor and its still doing the same thing it did when I took it.

Remove and Replace the cyl head [with valves] for valve bench cleaning. Might be useful if one were to port the valves, check spray patterns, etc. Excellent for inspection - there's some validity to it, but it's thin ice.

I know they are full of crap. I also turned in the stupid questionnaire today. I did asked for my money back for the coil pack they replaced without even so much as trouble shooting. Not till I brought the car back that afternoon did they bother to try the pack in another cylinder before deciding it was something else. If it was BMW they did this too BMW would have laughed at them. But no they have my money so hard luck. They gave me some crap about it should have been replaced when the plugs and injectors where so no refund.. LOL

I am thinking about filing a claim with my cc about this lot. 800 in parts and 2200 in labor and its still doing the same thing it did when I took it.

$3K and not have anything fixed is clearly ridiculous for a mass production car. That's Ferrari owner bills not a run of the mill BMW.

Main issue if probably taking it the dealer. They are used to warranty work and working on cars just out of warranty. It's doubtful many dealers see many cars with much over 80K miles as after the first repair bill most owners find an independent garage.

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Six Euro Deliveries since December 1998 (Owned E46, E90, E91, E92 and E93)

Back when I was an automotive tech, we used to have an intake cleaning kit that we could run on a car. You mounted a sprayer over the throttle body and injected over about 20 - 30 minutes a cleaning solution mist while the engine was running. It was similar to this: http://www.autogeek.net/3m-fuel-system-kit-08963.html Similar but it was a professional rig and not this hokey spray can. It really did a great job especially with the port fuel injection cars since no fuel would flow through the intake manifold.

Now I don't believe this would clean the valves once they are sufficiently dirty, but does anyone (DSXMachina for instance since he seems to have a lot of knowledge on this subject) know if this would be a good preventative measure? I'd have no problems running this every 30,000km or something. It wasn't overly expensive and was similar in price to a fuel injector cleaning.